Blade for concrete mixers



Feb. 10, 1931. c, M uc 1,791,880

BLADE FOR CONCRETE MIXERS I Filed Aug. '10. 1929 2 Shets-Sheet 2INVENTOR Patented Feb. 10, 19311 Qumran) STATES PAT NT o-FFiCE CIQABENCE MQTUC'K, or SEATTLE, wasnmerolxf; ASSIGN0RTVO-MQRRIS1 390 1133,,F j j11vc.,Aco1 aroRATIoN or wasnmemou' I BLADE non CONCRETEMFIXERSApplication t ed-An lia 10,1929. Serial N5. 384,306.

"- invention refers to-the art of transit concrete mixers, particularlythe type employing a fixed mixing chamber or U-shaped hopper and havinga revolvingshaft passing therethrough, to which: are secured mixingblades or paddles. More particularly my invention refers to a specialtype ofgblade for use in this type of mixer. I

V In the past a great deal ofidiificulty 'has :10 been encountered inproducing a mixer employing a revolving shaft within a fixedmixingchamber. This type of machine has been in use for years form1x1ng'gra1ns,fiouri and plaster and stucco. Repeated attempts have beenmade in the last few years to use this type of machine for mixingconcrete. When this was attempted, however, many problems arose, duelargely to the wide-variety of materialsused as aggregate'in theproduction of concrete. Concrete normally consists of cement, sand andvarying sizes of gravel to which water is added; The earlyexperimenters'with this typeof mixerin the concrete field found a markedI Jtendency for thelsmall bits ofgravelto be,-

come wedged inbetweenthe mixer shell and the paddle or blade?" Thiswould tend to spring the twozapart,-thus making'it possible for stilllarger rocks to wedge in, the finalresult'beingz that-either the armssupporting the paddles would 'breakjor the power re-"- quired todrivethe machine :wo'uldbe so great V V T The; principal object of myinvention. is to. M provide a blade construction which will make itpossible to satisfactorily construct amachine that may be used asatransit mixer.

A further object isto provide a blade; for

;a,transit concrebemixer which obviates all possibility of materialsbeing wedged in be:

- similar materials. It has been in use for some as tobe impractical. Itnaturally'follows that ifexcessive power is required, the,

weights become exces'sive and'it is impossible tween said blade and the$1191 1 of themixing drum. Y i i r A further object is to provide amixing I blade that may beldeflected under a heavy load and be-caus'edtoassume apo-sition which. I

Will lessen the power required to revol th mixer shaft, i r i i Afurther object is to providea mixer paddle that in thezfinal stage ofthe mixing operation will'scrape the mixer drum of all 450 adheredmaterials. 7

' A still further object isto'provide resilient -means' properlyprotected from the materials inwhich it'works 'forassisting in the abovenamed objects. I

A final object of my invention is to provide a removable'mixer bladewhich may be readily removed in case ofbreakage or in case a material"is to be mixed which is different than which the blades were originallyintendedto l mix.

I obtained thej above named :objects-and others inherent in :the samebythe devices 7 llustrated in the accompanying. drawings,

wherein: r 16 Figure l, is a; perspective view'ofone of mym'ixing bladesas removed from themachine; f,

Figure 2, is across-sectional view through thehub of'themixingblade,showing these spring construction and the associated parts.

- 1 FigureB, is a cross-sectional view-through a concrete mixer of'thetype mentioned showmg two forms'oi mybladesin place.

Figure-4,-is a top plan View looking directs lydown a propellingty-peofblade, b'l lgigure 5,'1s a top" plan view of a-stirring Figure 6; is across-sectional view one re- Referring to the drawings,{throughout iwhich like numerals indicate like parts -Numeral 10 designates the armproper;

7 which as a'matter ofcon'venience, I have made as a casting. i lheupper endlofarm 1 -0 v.is'

' enlarged toiiormkthe.hub 12; which imam, I.

to the hub 12, although I believe it will be apparent that the tube 16might be cast integral with the hub 12.

Chamber 14 serves as a housing for the 5 coiled torsion spring 18 whichhas one straight pressure can be applied to the packing by end 20adapted-to engage a hole 22, which I normally drill into the hub 12. Theother end 24 of spring 18 has a sharp downward bendwhich is bestillustrated in Figure 6 and is engaged by theslot 26. Slot 26 is formedin an outwardly'projecting hub 28' of the revolvable blade 30. Blade 30is supported and held in position by the bolt 82 which is, at one end,threaded into the hub 12 and is further provided with a jam nut 34.

In order that the blade 30, which is normally either cast iron or caststeel, will not rust to bolt 32, I normally provide a bushing 36 ofsuitable material, such as brass.

In order to insure a positive exclusion of all foreign material from thespring chamber 14, I provide a packing'38, which I have founditconvenient to retain in position by slightly counter-boring the tube 16andfitting in the counter-bore a washer 40. Any desired able arm 30 fromgoing forward of a radial.

line through the center of the mixer shaft and the center of bolt 82.This stop I find most simply'provided by a jaw clutch arrangement,

which is illustrated in Figures 2 and 6, and

consists of two interlocking jaw members 46 and 48, which are formed onthe hubs 28 and 12 respectively.

As the required movement of the blade 30 never exceeds 90 de rees, thelugs 46 and 48 can very conveniently be made to cover at least 90degrees and still give ample room for movement. I v

'In Figures 1' and 4 I have shown a fixed blade 50, which is set at anangle to the axis of bolt 32. I have also shown't-he blade 30 as set atsubstantially-the. same angle. This is to adapt my blade to that type ofmixer in which .a circulation' ofjmaterial desired.

In Figure 5 I have shown a straight blade 52 with a straightrevolvableblade 54. The

spring mechanism of'course, is identical with the construction of Figure4 and this type of blade finds awide variety of uses. For instance, in aoirculatingtype of mixer employing a plurality of blades, of the typeshown in Figure 4, the material is moved to one endiof'the mixing drumwhere'itwill tend to pack.- In a case of-this nature I have found itvery desirable to, employ 'one ,or

more bladesofthe type shown in Figure 5.

Further,'1n mixers of this general character where it is not desired tocirculate the 7 material but rather to mix it thoroughly and rely upon ahoisting device to raise one end of the mixer so that the finished mixwill pour therefrom, this type of blade may be used throughout.

I have found, however,

that for certain types of material,- it is desirable to modify thegeneral shape of blade 52. I have not illustrated the various forms thatmight be'used, as I do' not feel that there would be any inventioninvolved but rather ordinary mechanical judgment would select that typeof blade best suited for the material tobe mixed. 4

Blades shaped like cultivator teeth, as plow shares and'many' otherforms have been used. I have used at times combinations of the straightblade 523.116. the angle revolvable blade 30, andfoundunder certainconditions that it was the mostsatisfactory arrangement. p

r The method of securing arm 10 to the central mixing shaft 60 is amatter of personal judgment. 7 v

In the arrangement shown in Figure 3 I have employed'a "hollow tube asashaft and have welded to it a number of lugs 62 to Which the arms 10may be easily bolted;

In Figure 1 I have shown a wide palm or blade 66, which is pitched at anangle opposite that of the outer blades. This makes a simple solutionwhere it is desired to make a circulatingmix machine.

In operationthe spring 18 is so placed as tonormally hold the revolvableblade in its" full extended position where it comes to rest against thejaw clutch formedby the mem- -bers 46 and 48. In this position the blade30 is in close contact with the mixer shell 68. I-Iowever, as theblad'esare turned through theaggregate in mixing a batch of concrete,

(the turning effort required when theaggregates are dry, isYerv great.Consequently the blades 30 will fold back to a pointwhere they presentbut little resistance to the revolving of the shaft. When the mix hasbeen wet-ted, the resistance becomes but a fraction of the starting loadand thejblades again assume their shell 68.

However. from timeto time'small pebbles as is'illustrated in Figure 3and rocks to. pass'under theiblade. K In the final cleanup ofthelmachine, the

permit the blades 30 are. forced tightly against the shell and thusremove any of the materials that would normally tend to adhere to thesurface and eventually dry and harden there.

Having thus described my'inventionand its method of operation, Ibelieveits construction and operation will be clear to those pro er positionagainst the I may get in between'the blade '30 or the'blade -54 andxtheshell, leavinga crack there where still larger rocks may become wedgedin. It

is then necessary for lthebla'de to be deflected,"

skilled in the art. Manifestlyi however,

changes maybe made in the form, proportions and arrangement of parts ofmy invention Without departing from the spirit thereof. a

"What I claim is: 1. In a blade for concrete mixers a sup,,

porting arm, a fixed blade secured to saidtf arm, a revolvable bladepivotably secured to said supporting arm and resilient means adapted tonormally maintain sald revolvabl blade'in its extendedposition.

2. In a bladefor concrete mixers a supporting arm, a fixed blade securedto said arm" and a revolvable blade pivotably mounted .and resilientlymaintained in its normal Working position; r V

3. In a blade for concrete mlxers, a supporting arm, a fixed bladesecured to the upper end of said arm, a spring cavity shielded by saidblade, a revolvable bladepivoted coaxially with said spring cavity, acoil 1 spring secured at one end in said spring cavity and having itsother end secured to'said re'volvable blade, and stop means adapt-ed tolimit the forward movement of said revolvable blade.

4. In a blade for concrete mixers, asupporting arm, a fixed blade, aspring cavity,

a coil spring insaid cavity, a revolvable blade resiliently supported bythe coil spring and means-adapted to" prevent the entrance of foreignmaterialsinto said spring cavity.

5. In a blade for concrete mixers, a sup porting'arm; a hub at the outerend of the supporting arm; a pivot and binding member adjustably'secured to said hub; an angled blade, resiliently held inposition, revolvable on said pivot member, a'cavity adjacent said hub tohouse the means which'resiliently support'the revolvable blade and afixed blade positioned in front of said cavity to shield it and to serveasthe ber.

principal mixing mem- In witness whereof, I hereunto subscribe my namethis 25th day of July, A.D. 1929.

, CLARENCE M. 'rUoK.

